noaa-model-16276 North Atlantic Freshwater Forcing Model Data at 8.2ka Morrill, C.; LeGrande, A.N.; Renssen, H.; Bakker, P.; Otto-Bliesner, B.L. North Atlantic Freshwater Forcing Model Data at 8.2ka 2014-03-24 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/16276 Investigator C. Morrill Investigator A.N. LeGrande Investigator H. Renssen Investigator P. Bakker Investigator B.L. Otto-Bliesner earth science paleoclimate paleoclimatic modeling latitude,null,null,degree north,null,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling sea surface temperature,null,null,degree Celsius,monthly,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling sea ice cover,null,null,percent,monthly,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling meridional overturning streamfunction,null,null,cubic meter per second,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling surface air temperature,null,null,degree Celsius,monthly,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling precipitation,null,null,centimeter per year,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling salinity,sea surface,null,practical salinity unit,monthly,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling surface air temperature,null,null,degree Celsius,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling longitude,null,null,degree east,null,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling precipitation,null,null,centimeter per year,monthly,paleoclimatic modeling,null,null,N,null earth science paleoclimate model atmosphere model earth science paleoclimate model ocean model geoscientificInformation abrupt climate change Complete -90 90 -180 180 Geographic Region Global Global>LATITUDE >LONGITUDE None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII Morrill, C., A.N. LeGrande, H. Renssen, P. Bakker, and B.L. Otto-Bliesner 2013 Climate of the Past 9 955-968 10.5194/cp-9-955-2013

We compared four simulations of the 8.2 ka event to assess climate model sensitivity and skill in responding to North Atlantic freshwater perturbations. All of the simulations used the same freshwater forcing, 2.5 Sv for one year, applied to either the Hudson Bay (northeastern Canada) or Labrador Sea (between Canada's Labrador coast and Greenland). This freshwater pulse induced a decadal-mean slowdown of 10–25% in the Atlantic Meridional Overturning Circulation (AMOC) of the models and caused a large-scale pattern of climate anomalies that matched proxy evidence for cooling in the Northern Hemisphere and a southward shift of the Intertropical Convergence Zone. The multi-model ensemble generated temperature anomalies that were just half as large as those from quantitative proxy reconstructions, however. Also, the duration of AMOC and climate anomalies in three of the simulations was only several decades, significantly shorter than the duration of ~150 yr in the paleoclimate record. Possible reasons for these discrepancies include incorrect representation of the early Holocene climate and ocean state in the North Atlantic and uncertainties in the freshwater forcing estimates. STUDY NOTES: File names generally follow CMIP5/PMIP3 conventions, using the following abbreviations: Omon = ocean variables at monthly resolution (sea surface temperature, sea surface salinity, sea ice area percent) Oyr = ocean variables at annual resolution (meridional overturning streamfunction) Amon = atmosphere variables at monthly resolution (near surface air temperature, precipitation) Ayr = atmosphere variables at annual resolution (near surface air temperature, precipitation) ehControl = Early Holocene (8.5 ka) control simulation ehMWP = Early Holocene meltwater pulse experiment piControl = PreIndustrial control simulation piMWP = PreIndustrial meltwater pulse experiment r<N>i<M>p<L> = Ensemble member designation, with N representing realization number, M representing initial condition method, and L representing "perturbed physics" number Note that GISS Model-E-R output are provided as multi-decadal or decadal averages of either monthly (Omon, Amon) or annual (Oyr) means. Multi-decadal (30-year) averages are provided for the control simulation and decadal (10-year) averages for the meltwater pulse experiment. Also, please note that anomalies for the GISS Model-E-R must be calculated as the 10-yr mean of the MWP experiment less the 30-yr mean of the closest control years. See provided ncl scripts (fig1_Morrill_etal_2013.ncl, etc) for more details on how to calculate GISS Model-E-R anomalies. DATA FILE LIST (sizes in MB and names) 0.1 8ka-precip-ensemble.nc 0.1 8ka-temp-ensemble.nc 68.9 CCSM_Amon_ehControl_r1i1p1.nc 69.0 CCSM_Amon_ehControl_r1i2p1.nc 34.5 CCSM_Amon_ehMWP_r1i1p1.nc 69.0 CCSM_Amon_ehMWP_r1i2p1.nc 851.5 CCSM_Omon_ehControl_r1i1p1.nc 853.7 CCSM_Omon_ehControl_r1i2p1.nc 426.7 CCSM_Omon_ehMWP_r1i1p1.nc 427.4 CCSM_Omon_ehMWP_r1i2p1.nc 15.0 CCSM_Oyr_ehControl_r1i1p1.nc 20.0 CCSM_Oyr_ehControl_r1i2p1.nc 5.0 CCSM_Oyr_ehMWP_r1i1p1.nc 10.0 CCSM_Oyr_ehMWP_r1i2p1.nc 6.1 GISS-E-R_Amon_piControl_r1i1p1.nc 5.5 GISS-E-R_Amon_piMWP_r1i1p1.nc 4.4 GISS-E-R_Omon_piControl_r1i1p1.nc 4.0 GISS-E-R_Omon_piMWP_r1i1p1.nc 0.3 GISS-E-R_Oyr_piControl_r1i1p1.nc 0.3 GISS-E-R_Oyr_piMWP_r1i1p1.nc 8.3 LOVECLIM_Ayr_ehControl_r1i1p1.nc 8.3 LOVECLIM_Ayr_ehMWP_r1i1p1.nc 350.5 LOVECLIM_Omon_ehControl_r1i1p1.nc 350.9 LOVECLIM_Omon_ehMWP_r1i1p1.nc 1.4 LOVECLIM_Oyr_ehControl_r1i1p1.nc 1.4 LOVECLIM_Oyr_ehMWP_r1i1p1.nc

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/gcmoutput/morrill2013/ncl-scripts/ Data Folder; NCL Scripts to Make Figures GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/gcmoutput/morrill2013/morrill2013-readme.txt Study Description; Readme File GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/gcmoutput/morrill2013/ Data Folder; netCDF Files USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11